Human pathogenic bacterium induces actin phosphorylation to selectively regulate

描述（由申请人提供）：许多细菌病原体在进入/内化或在细胞间传播期间利用宿主肌动蛋白细胞骨架。病原体在节肢动物载体中对肌动蛋白细胞骨架的利用尚未被探索。使用硬蜱肩胛蜱和Anaplasma phagocytophilum（人粒细胞无形体病的代理人）作为感染模型，我提供的证据，第一次显示一个专性细胞内的细菌可以利用肌动蛋白细胞骨架来控制节肢动物基因转录为自己的利益。初步结果表明，A.嗜吞噬细胞菌诱导蜱肌动蛋白的磷酸化，并随后改变单体/丝状（G/F）-肌动蛋白的比率。我还表明，A.嗜吞噬细胞诱导的肌动蛋白磷酸化依赖于Ixodes PAK 1-PI 3激酶信号传导。A.嗜吞噬细胞诱导的肌动蛋白磷酸化导致核G-肌动蛋白和磷酸化肌动蛋白增加，与RNA聚合酶II（RNAPII）相关。在细胞核中诱导的肌动蛋白磷酸化增强了TATA盒结合蛋白与RNAPII的结合，并引起了对A.嗜吞噬细胞存活。本项目旨在研究Salp 16启动子在A.嗜吞噬细胞菌感染建议进行额外的研究以确定是否有任何细菌组分或其他硬蜱转录激活因子参与这种特定的基因调控。总的来说，这项研究可能提供的证据肌动蛋白磷酸化在宿主-病原体相互作用的新作用，并提出新的策略，干扰这种专性细胞内病原体的生命周期，也许其他立克次体相关的微生物的医学重要性。 公共卫生相关性：在美国，肩突硬蜱传播几种人类病原体，包括A。嗜吞噬细胞菌，人类无形体病的病原体。这种细菌在其载体宿主中生存的分子机制目前尚不清楚。这个项目的建议提供了一个新的作用，肌动蛋白在宿主-病原体相互作用的证据，并建议新的策略，干扰这种专性细胞内病原体的生命周期，也许其他节肢动物传播的微生物的医学重要性。

DESCRIPTION (provided by applicant): Many bacterial pathogens exploit host actin cytoskeleton either during entry/internalization or spread from cell to cell. Pathogen use of the actin cytoskeleton in arthropod vectors has not yet been explored. Using Ixodes scapularis ticks and Anaplasma phagocytophilum (the agent of human granulocytic anaplasmosis) as an infection model, I provide evidence for the first time to show how an obligate intracellular bacterium can exploit the actin cytoskeleton to control arthropod gene transcription for its own benefit. My preliminary results show that A. phagocytophilum induces the phosphorylation of tick actin and subsequently alters the ratio of monomeric/filamentous (G/F)-actin. I also show that A. phagocytophilum-induced actin phosphorylation is dependent on Ixodes PAK1-PI3kinase signaling. A. phagocytophilum-induced actin phosphorylation resulted in increased nuclear G-actin and phosphorylated actin that associated with RNA Polymerase II (RNAPII). Induced actin phosphorylation in the nucleus enhanced binding of TATA-box-binding-protein to RNAPII and caused the selective regulation of salp16, a gene crucial for A. phagocytophilum survival. This project proposal explores to identify the mechanism by which selective regulation of salp16 promoter is mediated upon A. phagocytophilum infection. Additional studies are proposed to identify whether any of the bacterial component(s) or other Ixodes transcriptional activator(s) are involved in this specific gene regulation. Collectively, this study may provide evidence for a novel role of actin phosphorylation during host- pathogen interaction and suggest new strategies to interfere with the life cycle of this obligate intracellular pathogen, and perhaps other Rickettsia-related microbes of medical importance. PUBLIC HEALTH RELEVANCE: In United States, Ixodes scapularis ticks transmit several human pathogens including A. phagocytophilum, the agent of human anaplasmosis. The molecular mechanisms that this bacterium uses to survive in its vector host are currently not understood. This project proposal provides evidence for a novel role of actin during host-pathogen interaction and suggests new strategies to interfere with the life cycle of this obligate intracellular pathogen, and perhaps other arthropod-borne microbes of medical importance.